Slack-thread-take-up mechanism for blindstitch sewing-machines.



T. J. HAYES.

SLACK THREAD TAKE-UP MECHANISM FOR BLINDSTITCH SEWING MACHINES.

I APPLICATION FILED OCT. 3, 1914.

1 ,25fi38. Patented Nov. 6,1917.

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WiTnesses. \nvenior". WWW Thomas \J. Hayes.

or ran era as PATNT on on THOMAS-J. HAYES, OF ROSLINDALE, MASSACHUSETTS, ASSIGNOR' TO ARBETTER IEELLING MACHINE COMPANY, 0F BOSTON, MASSACHUSETTS, ACORPORZATION OF MAINE.

SLACK-THREAD-TAKE-U? MECHANISl/L FOB-BLINDSTiTCH SENING-MACHINES.

- Specification of Letters Patent.

Patented Nov. 6, 1917..

Application filed. October 3, 1914'. Serial No. 864,711.

To (ZZZ-whom it may concern:

Be it known that I, THOMAS J. Hares, a citizen of the United States, and resident of 'Roslindale, county of Suffolk, State of Massachusetts, have invented an Improvement in Slack-Thread-Take-Up Mechanism for Blindstitch Sewing-Machines, of which the following description, in connection with the accompanying drawing, is a specification, like characters on the drawing representing like parts.

T his invention relates to improvements in thread controlling mechanism for sewing machines and particularly to the slack thread take up mechanism which measures the amount of needle thread given as said thread is engaged by the complementary stitch forming mechanism such as the revolving hook shuttle or looper. In machines heretofore, constructed the slack thread take up mechanism has not been arranged to pull oif a uniform amount of thread and at times more thread than is necessary to pass around the bobbin is turned off by the take-up. W hen such an excess amount of thread is given out the stitch may be improperly set and furthermore, in machines using a curved oscillating needle having a thread groove in the convex portion thereof the delivery of an excessive amount of thread is likely to cause the same to become dislodged from the thread guiding groove of the needle so that upon the next stroke the thread is severed by the sharp walls of the thread groove in the needle, especially where the needle cooperates with a needle guide for directing it in its proper path through the work.

One of the objects of the invention is to provide means whereby a uniform amount of thread willbe delivered to the needle in such a manner that a slight tension upon the thread will be maintained while the same is engaged by the complementary stitch forming mechanism so that the thread will be pulled off of the beak of the hook positively during the movement of the hook which causes the concatenation of the thread. 1

Anotherobject of the invention is to provide a constant tension upon the thread such as will prevent the same from jumping out of thethread slot in the needle and thereby prevent the breaking or cutting of'the thread.

In slackthread take-ups heretofore constructed the thread engaging spring has, so far as I am aware, always contacted with a relatively thin wall whichin the course of time wears the thread engaging member and causes the same to become bent or broken;

' Another object of theinvention is to pro vide a relatively wide surface toarrest the thread. engaging member so that the likelihood of breakage or deformation of said member will be prevented. Other objects of the invention will. more fully appear from the following description and the accompanying drawings and. will be particularly pointed out in the annexed claims.

In the drawings:

Figure l is a side elevation of' a portion of the base, an arm and the head of'a usual type of sewing machine showing the improved slack thread take-up. attached to the head and the relative positions of the tension slack thread take up, the take-up and the curved'oscillating needle.

Fig. 2 is a detail side elevation of the slack thread take-up embodying this invention, .7

Fig; 3 is a detail front elevation of the take-up, and

Fig; at is a detail view in perspective of the adjustable stop for the threadengaging member of the slack thread take up.

The invention is disclosed herein as ap-' plied'to a sewingmachine for felling having a curved oscillating needle although it is to be understood that the same maybe applied to other types of sewing machines.

The'machine herein illustrated comprises a bed plate 1' which supports the feeding mechanism, a bender mechanism and. an ad} justable work support 2, the usual arm of the sewing machine 3 carrying the main driving shaft 4} and terminating in a head 5' which contains the'mechanism for 'actuating the curved oscillating. needle 6. The complementary stitch forming mechanism may'com'prise a revolving hook or'looper 7- andif desired an upper feed 8 may bes'uit-I- ably actuated from cams or links 7 Within the head of the machine.

The main take-up comprises an arm 9 pivotally mounted upon a stud 10 and having an offset portion 11 provided with a stud 12 engaging a suitable cam 13 mounted uponthe main shaft'4 of the machine. A tension device 14 is desirably located on the sewing machine arm adjacent the upper portion of the head and the slack thread takeup 15 desirably is located upon a boss 16 projecting laterally from the lower portion of the sewing machine head directly beneath the tension member 14 so that the thread coming from the spool (not shown) to the tension device will run directly downward to an annular guide upon the slack thread take-up, thence through a guide 17 in the end of an adjustable member 18, through an eye 19 in the end of a resilient arm 20, thence through a thread guide 21 in the end of the take-up arm 9 and finally to the needle 6.

The slack thread take-up preferably is composed of a pair of disks 22, 23, sup ported upon a suitable stud and spaced apart by a central grooved collar 24 forming an annular thread guide, said disks being secured together and to the boss 16 by a screw 25.

A recess 26 is formed in the boss 16 axially of the disks 22, 23 and an adjustable stud 27 is mounted therein. The slack thread take-up arm is desirably in the form of a helical spring 28 one end of which is conveniently anchored in a slot in the stud 27, the other end of said spring being extended substantially tangentially to the annular thread guiding surface of the grooved collar 24 to form a slack thread take-up arm 20. This arm preferably is bent at right angles near its end in order to present the thread eye 19 in the end thereof in proper position to the path of the thread leading from the annular thread guide 24 to the guide 21 of the take-up arm 9.

8 no means for limiting the upward movement of the slack thread take-up arm so that it does not always measure a uniform amount of thread. In order to overcome this difficulty I have provided a limiting stop member 18 which preferably is in the form shown in Fig. 4 comprising an are shaped portion 31 having a slot 32 adapted to receive a screw 33 by means of which it may be adjustably attached to the boss 16. The arcshaped stop member 18 may be formed of sheet metal by stamping and desirably is constructed with a lip portion 34 which when in position will arrest'the downward movement of the thread engaging arm 20. By reason of the fact that the lip portion24 presents a broad surface all injury to the thread engaging arm 20 will be avoided.

The stop member 18 is desirably provided with a tangentially extended portion 35 having a laterally oifset end 36 provided with a thread guide 17 having a slot 37 leading thereto. In the construction of the stop member 18 the distance between the under face of the end portion 36 and the lip 34 may be so designed as to permit precisely the amount of thread to be drawn off by the slack thread take-up which is required to be manipulated by the revolving hook, looper or other complementary stitch forming member. By reason of the resilience of the thread engaging member 20 the thread will always be under a slight tension while it is engaged by the revolving hook or the looper and will be positively pulled off of the beak thereof as soon as the hook reaches castingoff position. The constant tension upon the thread also maintains the thread within the groove in the back of the needle, and the possibility of the thread becoming broken or cut by the needle will be avoided.

By reason of the adjustability of the stop member 18 the thread guide 17 at the end thereof may be placed substantially in alinement with the thread guide 21 in the end of the take-up arm 9 and the annular guide 24 so that when the take-up arm 9 is at its highest point the thread will run in approximately a straight line from the annular guide 24 of the slack thread takeup to the guide 21 of the main take-up arm the adj ustment permitting the same to be arranged properly upon any individual machine so that the same may be adapted to any machine requiring a slack thread take up. This adjustment also serves to permit the slack thread take up to be so positioned that it will properly cooperate with the movements of the needle and complementary stitch forming mechanism.

l Vhile the slack thread take-up mechanism disclosed herein is the preferred embodiment of my invention it will be understood that other embodimentsthereof may be made within the scope and meaning of the following claims.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is: 1

1. A slack thread take-up for sewin machines comprising a central stud having a thread guiding surface, a spring actuated take-up member having a thread engaging arm movable in an arcuate path relatively to said stud and a stop member having a broad lip havingthe same radial arrangement relatively to said stud as the take-up arm for limiting the movement of said arm under the impulse of its spring whereby bending of the arm by repeated continued impact of the stop is avoided.

2. A slack thread take-up for sewing machines comprising a central stud having a thread guiding surface, a spring actuated take-up member having a thread engaging arm movable in an arcuate path relatively to said stud, a stop member for said arm comprising a plate having a recess to receive said take-up arm, one end wall of said recess being provided with a lip presenting a. broad surface for limiting the movement of said arm under the impulse of its spring and the opposite end wall presenting a stop for limiting the movement of the arm in the opposite direction.

3. A slack thread take-up for sewing machines comprising a central stud having a thread guiding surface, a. spring actuated take-up member having a thread engaging arm movable in an arcuate path relatively to said stud, a stop member for said arm provided with a guide for the thread and having means located in fixed relation to said guide for limiting the throw of said arm in both directions whereby uniform action of the take-up arm upon the thread is maintained.

A slack thread take-up for sewing machines comprising a central stud having a thread guiding surface, a spring actuated take-up member having a thread engaging arm movable in an arcuate path relative to said stud, a stop member for said arm provided with a guide for the thread and having means located in fixed relation thereto for limiting the throw of said arm in both directions whereby uniform action of the take-up arm upon the thread is maintained, and means for adjusting said member to position said arm properly to cooperate with the needle and complementary stitch forming mechanism.

5. A slack thread take-up for sewing machines comprising a central stud having an annular thread guiding surface, a helical, spring secured to said stud and having an extension disposed substantially tangentially to said thread guiding surface and provided at its end with a thread eye, adjustable means for limiting the extent of movement of said extension comprising a recessed stop having a broad lip positioned substantially tangentially to said thread guiding surface adapted to arrest the downward movement of said extension.

6. A slack thread take-up for sewing machines comprising a central stud having an annular thread guiding surface, a helical spring having a resilient thread engaging member disposed substantially tangentially to said thread guiding surface, means for limiting the movement of said thread guiding member comprising a recessed stop positioned substantially tangentially to said annular thread guiding surface presenting abroad lip adapted to arrest the downward movement of the thread engaging member and having an extension in the path of the thread engaging member to limit its upward movement.

7. A slack thread take-up for sewing machines comprising a central stud having an annular thread guiding surface, a helical spring having a resilient thread engaging member disposed substantially tangentially to said thread guiding surface, means for limiting the movement of said thread guiding member comprising a recessed stop positioned substantially tangentially to said annular thread guiding surface presenting a broad lip adapted to arrest the downward movement of the thread engaging member and having an extension in the path of the thread engaging member to limit its upward movement provided with a thread guide to direct the thread between the annular thread guiding surface and the thread engaging member.

8. The combination with a sewing machine comprising a head having a laterally extending cylindrical boss, of a slack-thread takeup comprising a stud anchored centrally of said boss and having an annular thread guiding surface, a resilient thread guiding member secured to said stud and means for limiting the extent of movement of said thread guiding member comprising an arcshaped member adapted to embrace said cylindrical boss and adjustably secured thereto, said member having a broad lip positioned in the path of said thread engaging arm and an offset portion provided with a thread eye, said offset portion being adapted to limit the upward movement of the thread engaging arm, the said thread eye to direct the thread intermediate of the annular thread guiding surface and the thread eye of the thread engaging arm.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

THOMAS J. HAYES.

Witnesses:

NATHAN HEARD, THOMAS J. DRUMMOND.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. G. 

